The invention relates to a switched-mode power supply device configured to control an output voltage by switching operation.
In a technique proposed for a power converter, EMI (Electro-Magnetic Interference) noise is reduced by increasing a gate resistance at certain timing determined based on: a result of comparing a pulse width of a generated control pulse and a predetermined pulse width threshold value; and a result of comparing information on estimated device temperature and a predetermined temperature threshold value (see Japanese Patent Application Publication No. 2011-166920 (Patent Document 1), for example).